Normal and white muscle diseased (WMD) lambs produced from ewes fed either low selenium alfalfa hay or synthetic diet with no vitamin E or selenium are proposed to be used in these studies. WMD is a selenium and vitamin E responsive myopathy. Selenium has been found to be associated with the synthesis of certain hemoproteins. For this and other reasons, mitochondria will be isolated from liver, heart and muscle of these lambs, and the ADP:O ratios and respiratory activity determined. This will be followed by studies on the determination of the cytochrome content in mitochondria from tissues of these lambs. Administration of inorganic selenium to animals prevents selenium deficiency disorders, and it is suspected that this is converted to organic forms in the biological system in order to bring about these responses. Therefore, the chemical form of selenium incorporated in mitochondria, microsomes or in a major selenium containing protein of the soluble fraction will be investigated. Calcium accumulates in the skeletal muscle of WMD lambs, and a crude fraction of sarcotubular membranes from muscle of these animals cannot sequester calcium. Therefore, these membranes will be isolated from the muscle of normal and WMD lambs for chemical characterization. The chemical properties of the membranes from these two sources should give some clues to the possible involvement of vitamin E and selenium in proper calcium metabolism.